qga: fix guest-get-disks regression

Commit 54aa3de72 ("qapi: Use QAPI_LIST_PREPEND() where possible")
inadvertently removed the has_dependencies from the partition disk
info, resulting in empty list being returned.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1950833

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20210420125831.233092-1-marcandre.lureau@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 4299ebd..75dbaab 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -1376,6 +1376,7 @@
         partition = g_new0(GuestDiskInfo, 1);
         partition->name = dev_name;
         partition->partition = true;
+        partition->has_dependencies = true;
         /* Add parent disk as dependent for easier tracking of hierarchy */
         QAPI_LIST_PREPEND(partition->dependencies, g_strdup(disk_dev));